#include <bits/stdc++.h>
using namespace std;
#define ll long long

int main() {
	ll n;
	cin >> n;

	ll cnt = 0;
	ll sum;

	for (ll i = 1; i <= n; i++) {
		ll t = i;
		sum = 1;

		for (ll k = 2; k <= sqrt(i) + 1; k++) {
			int factor_cnt = 0;
			while (t % k == 0) {
				factor_cnt ^= 1;
				t /= k;
			}
			if (factor_cnt & 1)
				sum *= k;
		}
		if (t != 1)
			sum *= t; // sum为 出现奇数次的质因子之积

		ll x = sqrt(n / sum);
		cnt += x;
	}

	cout << cnt;
	return 0;
}